|Small block Chevy engine project
||Last updated on June 10, 2012|
Zora Arkus-Duntov's Memo to Chevrolet
Thoughts Pertaining to Youth, Hot Rodders, and Chevrolet|
The Hot Rod movement and interest in things connected with hop-up and speed is still growing. As an indication: the publications devoted to hot rodding and
hop-upping, of which some half-dozen have a very large circulation and are distributed nationally, did not exist some six years ago.
From cover to cover, they are full of Fords. This is not surprising that the majority of hot rodders are eating, sleeping, and dreaming modified Fords. They
know Ford parts from stern to stern better than Ford people themselves.
A young man buying a magazine for the first time immediately becomes introduced to Ford. It is reasonable to assume that when hot rodders or hot rod-influenced
persons buy transportation, they buy Fords. As they progress in age and income, they graduate from jalopies to second-hand Fords, then to new Fords.
Should we consider that it would be desirable to make these youths Chevrolet-minded? I think that we are in a position to carry out a successful attempt.
However, there are many factors against us:
Loyalty and experience with Ford.
Hop-up industry is geared with Ford.
Law of numbers: thousands are and will be working on Fords for active competition.
Appearance of Ford’s overhead V-8, now one year ahead of us.
When a superior line of GM V-8s appeared, there where remarkably few attempts to develop these, and none too successful. Also, the appearance of the V-8
Chrysler was met with reluctance even though the success of Ardun-Fords conditioned them to the acceptance of Firepower.
This year is the first one in which isolated Chrysler development met with successes. The Bonneville records are divided between Ardun-Fords and
Like all people, hot rodders are attracted by novelty. However, bitter experience has taught them that new development is costly and long, and therefore they
are extremely conservative. From my observation, it takes an advanced hot rodder some three years to stumble toward the successful development of a new design.
Overhead Fords will be in this stable between 1956 and 1957.
The slide rule potential of our RPO V-8 engine is extremely high, but to let things run their natural course will put us one year behind - and then not too
many hot rodders will pick Chevrolet for development. One factor which can largely overcome this handicap would be the availability of ready-engineered parts
for higher output:
If the use of the Chevrolet engine would be made easy and the very first attempts would be crowned with success, the appeal of the new RPO V-8 engine will take
hold and not have the stigma of expensiveness like the Cadillac or Chrysler, and a swing to Chevrolet may be anticipated. This means the development of a range
of special parts - camshafts, valves, springs, manifolds, pistons, and such - should be made available to the public.
To make good in this field, the RPO parts must pertain not only to the engine but to the chassis components as well. In fact, the use of light alloys and brake
development, such as composite drums and discs, are already on the agenda of the Research and Development group.
These thoughts are offered for what they are worth: one man’s thinking aloud on the subject.
December 16, 1953
The 2007 Chevy R07 NASCAR engine
April 14, 2007 GM press release|
GM Racing White Paper: Inside the New Chevrolet R07 Small-Block V-8
Technical Insights on GM's First Purpose-Built Small-Block V-8 NASCAR Racing Engine
Detroit – For the first time since 1955, Team Chevy is introducing an all-new small-block V-8 engine in the top tier of stock car racing. The new Chevrolet
R07 is the first purpose-built engine designed and developed by GM Racing specifically for NASCAR Nextel Cup competition. This purebred engine is the successor
to the production-based powerplants that have made Chevrolet the most successful manufacturer in NASCAR history. This white paper highlights the Chevrolet
R07's development and summarizes its technical features.
Design and Development
The Chevrolet R07 is succeeding the championship-winning SB2 (Small-Block/2nd Generation) engine that has been used by GM teams in NASCAR Cup racing since
1998. NASCAR approved the Chevrolet R07 for competition in 2007, and it is expected that the R07 small-block V-8 will become the exclusive Chevrolet powerplant
in the Nextel Cup series as teams turn over their inventory of SB2 engines and components.
Work on a successor to the SB2 began in earnest in 1999, and several variations of the conventional small-block V-8 were designed, tested, and evaluated. In
2004, NASCAR held discussions with the automotive manufacturers about a possible "Engine of the Future" that paralleled the Car of Tomorrow body/chassis
program. Although the Engine of the Future did not become reality, the meetings did establish a framework for future NASCAR engines.
"The discussions with NASCAR and the other manufacturers about the Engine of the Future were extremely productive," said Jim Covey, NASCAR engine development
manager for GM Racing. "Although the Engine of the Future program was put on the shelf in 2005, NASCAR Nextel Cup Series director John Darby developed a list
of parameters that define the envelope for all manufacturers, thus giving Chevrolet an opportunity to develop the R07 engine. This 'box' set the boundaries
for specific design features and minimum and maximum dimensions for key engine components.
"We had already started to lay the foundation for a future Chevrolet engine, and we were able to adapt that design to the Chevrolet R07," Covey continued.
"That was the key to designing, testing and submitting the engine for approval on a very tight schedule. A prototype R07 engine was running durability tests on
a dyno six months after we kicked off the program. The R07 engine development team included Ed Keating and Ron Sperry, who focused on cylinder heads and intake
manifolds, and Ondrej Tomek, who was responsible for the cylinder block. We also worked with our key Chevrolet teams, GM Powertrain, and our
Just as in all forms of motorsports, the rulebook defined the basic engine package. GM Racing's objective was to produce the most competitive and reliable
engine within the boundaries established by NASCAR.
"NASCAR's box provides considerable latitude for manufacturers to design their engines, and there are many parameters that have to be balanced," explained Pat
Suhy, GM Racing Group Manager, Oval Track. "If a manufacturer maximizes one aspect of the engine design then it may limit what can be done in another area. Our
goal at GM Racing was to find the optimum point for all of them. We relied on our computer-aided engineering and design tools, our experience, and input from
our affiliated teams to make informed decisions on the engine configuration. It was all about balancing those tradeoffs to produce an engine that would
produce competitive power with exceptional reliability while also improving safety and reducing costs for Chevy teams."
Many of the advanced technical resources used by GM Racing engineers to develop the Chevrolet R07 racing engine are also used to develop GM production engines.
By employing technology such as computational fluid dynamics (CFD), finite element analysis (FEA), and solid 3D modeling, GM Racing engineers were able to
evaluate and analyze various designs in computer simulations. This extensive use of computer modeling also accelerated the production of prototype parts after
the specifications were finalized.
While CFD is commonly associated with aerodynamic development of race cars, it can also be used to analyze the behavior of fluids such as the coolant flow
through the Chevrolet R07's block and cylinder heads. FEA was used to analyze the strength and minimize the weight of the R07's block and cylinder
"Although we use many of the same engineering tools, the timeframe for racing engines is much shorter than it is for production engines," Suhy noted. "The
rapid turnaround in racing allows us to get feedback on the accuracy of GM's computer simulations and models very quickly. The same programs can then be
refined to make them more accurate when used to develop future production engines."
In this way, the Chevrolet R07 racing engine will lead to better production GM powerplants. "The concepts and processes that are used to improve the
performance of our racing engines are shared with the production engine designers to improve the efficiency of our production engines," said Tom Stephens,
group vice president of GM Powertrain.
The Chevrolet R07 retains the pushrod/two-valve layout that has been the mainstay of American motorsports since the introduction of the first-generation GM
small-block V-8 in 1955. This classic design has now evolved into a highly advanced racing engine.
Per NASCAR specifications, the Chevrolet R07 displaces a maximum of 358 cubic inches with a maximum cylinder bore diameter of 4.185 inches. The block is a
precision iron casting with integral oil and coolant passages that eliminate the need for most exterior lines. The distance between the Chevrolet R07's
cylinder bores is 4.500-inch (vs. 4.400 inches in the SB2 small-block). This wider bore spacing improves coolant circulation around the cylinder barrels. In
conjunction with a targeted cooling system, the R07 block design minimizes temperatures at critical locations.
The R07 block has a new six-bolt head bolt pattern instead of the small-block's traditional five-bolt design. The revised head bolt pattern improves head
gasket sealing and reduces cylinder bore distortion.
The R07's camshaft is located higher in the block than the camshaft in the SB2. The raised cam operates pushrods that are correspondingly shorter and stiffer,
thereby improving valvetrain dynamics at high rpm. The raised cam also provides clearance for inboard piston squirters that spray the underside of the pistons
with oil for cooling. The camshaft tunnel is isolated from the crankcase to minimize windage losses caused by oil falling onto the rotating crankshaft
assembly from the cam and to contain the valvetrain parts in the event of breakage.
In contrast to the SB2's "mirror port" cylinder heads, the Chevrolet R07's aluminum cylinder heads resemble production LS-series small-block cylinder heads
with alternating intake and exhaust valves. The R07's shallow valve angle produces a compact, efficient combustion chamber design that produces the required
compression ratio with a lightweight flat-top or slightly domed piston. GM Racing engineers optimized the R07's intake port layout for the single, centrally
mounted four-barrel carburetor mandated by NASCAR.
The aluminum intake manifold has an extended plenum to equalize fuel distribution among the cylinders. The manifold is dry; a separate valley cover carries
coolant from the cylinder heads. The R07's distributor is located at the front of the engine to facilitate adjustments in ignition timing.
The Chevrolet R07 rocker covers are rigid cast aluminum with O-ring seals. The covers incorporate integral valve spring oilers that are pressure fed from
passages in the cylinder heads, eliminating the need for external oil lines. GM Racing also designed a high-efficiency water pump and a carbon fiber front
cover that shields the aftermarket camshaft belt drives used by NASCAR teams.
The R07 has provisions for driving a conventional diaphragm fuel pump off of the camshaft. A remote-mounted mechanical fuel pump can also be driven via a cable
from the rear of the camshaft. When using the cable drive, the fuel pump can be relocated to the rear of the car near the fuel cell. This enhances safety in an
accident by mounting the fuel pump in a less vulnerable location.
"Chevy NASCAR teams were deeply involved in the design of the Chevrolet R07," said Suhy. "We meet monthly with representatives from our four key partners –
Hendrick Motorsports, Richard Childress Racing, Joe Gibbs Racing and Dale Earnhardt, Inc. – to get their input on how we can make Chevrolet racing engines
more reliable and easier to build and service. Many of their ideas were incorporated in the R07's final design, such as the integration of the oil and cooling
"It's not about helping our affiliated teams to build the most powerful engine because each of them has developed their own proprietary parts and processes,"
he noted. "GM Racing's role is to provide premium quality, easy-to-use components. We want Chevy teams to be able to devote more of their energy and resources
to winning races and less energy to preparing engines."
The introduction of the Chevrolet R07 small-block V-8 represents another milestone in the continuous evolution of the small-block V-8 engine. GM's first
purpose-built NASCAR racing engine was designed, built and tested to continue Team Chevy's winning tradition in NASCAR.
Our Chevy 327 engine project
On this page we'll follow the progress of building a mild and inexpensive 327 street engine for a
traditional '32 Ford coupe built with a late-Fifties or early-Sixties theme. This engine won't be anything
exotic, just some neat old parts and a bit of attention to detail.|
The project began in March of 2006, with a standard-bore, small-journal 327 block and a pair of 462 fuelie heads that I found for sale here in Phoenix. The
block was bought for $50, and the pair of heads cost another $100. These parts are perfect for what this project is all about.
The dual-plane Brodix intake was found on eBay. It had been powdercoated silver, and used on a Camaro drag car. Leaking race gas had stained the powdercoating,
and it looked so bad nobody else wanted it. I won the auction for $90, sandblasted it, and then worked it over with a variety of abrasives.
Back in 1993, when I lived just north of Charlotte, North Carolina, I bought this pair of 1960s Cal Custom six-finned valve covers for $5. They are shown here
after a bit of work with files and emery cloth. You can see the result of filing and sanding the valve covers between the fins.
The Enderle timing cover was given to me by Russ Meeks, so what you see here cost me a total of $245.
Here's the Edelbrock SY1 intake manifold, which is also known as the Edelbrock Smokey Ram.
Thanks to Craigslist, I bought this in January of 2009. It's a fairly rare piece.
The Smokey Ram was developed by Smokey Yunick for SCCA Trans AM racing. The dual-quad predecessor of this manifold carried a Chevrolet part number and was used
in the 1969 Z/28 Camaro 302 engine.
The single-carb Edelbrock version was introduced in 1972.
The casting number on the small-journal 327 block is 3858174.|
Blocks with this casting number were used in cars that were made from 1964 through 1967, including the 1966 Corvette.
Here is the right side of the block after it was sent out to SX Obsolete Engine Parts here in Phoenix, where it was hot-tanked and acid-dipped.|
This the left side of the block after it was cleaned. We were hoping that all of the rust would be gone after the acid-dipping, but the block had been outside
for years and had a lot of rust on it.|
This the left side of the same block after I spent two hours working it over with abrasives.|
After final machining and cleaning, the block will get painted to match the car. By prepping the outside of the block this way, we'll have smooth, even
surfaces under the paint, and it should look pretty good.
Here's what the rear main cap looked like after the block was hot-tanked.|
This is the same main cap, after I spent a few minutes using small emery cloth cartridge rolls to put a radius around the drain hole to make it easier for the
oil to flow.|
Here's a close-up of the stock main cap.|
This is the same main cap after cleaning it up a bit and adding the radius.|
This picture was taken after the block was torn down, hot-tanked, inspected, and acid-dipped.|
As they were found, the 462 heads were bare, clean, and in good shape.
The intake ports are essentially untouched. They will be gasket-matched along with the intake manifold.
The combustion chambers have been smoothed out and the polishing has been started.
The exhaust ports have been gasket-matched to a Fel-Pro copper gasket and shaped with abrasives. The next step is to get them smoother.
Here's one of the first valve covers Cal Custom made. Unlike the die-cast, six-finned valve covers that are shown on the engine, this was sand-cast and has
seven fins. This piece is NOS, and was likely made in the late '50s or early '60s.
This is a used pair of the early, seven-finned Cal Custom valve covers that were found on eBay. The castings are rough, but they have been smoothed out with
When I bought a cherry Stewart Warner 9,000-rpm mechanical tach on eBay, the seller included an old dual-point, tach-drive distributor.
Here's a closer look at the dual-point distributor. Checking the number, 1110985, shows that it is the correct piece for a 1962 Corvette.|
This will be used along with an MSD 6AL ignition.
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